Forming apparatus for profile grinding wheels



y 1951 H. s. HALLEWELL 2,985,163

FORMING APPARATUS FOR PROFILE GRINDING WHEELS Filed July 21, 1958 5 Sheets-Sheet 1 lA/VE/VTOR Map ATTORNE) May 23, 1961 H. s. HALLEWELL' FORMING APPARATUS FOR PROFILE GRINDING WHEELS Filed July 21, 1958 3 Sheets-Sheet 2 May 23, 1961 H. s. HALLEWELL 2,985,163

FORMING APPARATUS FOR PROFILE GRINDING WHEELS Filed July 21, 1958 3 Sheets-Sheet 3 //V VE/V TOR y M W ATTORNEY FORMING APPARATUS FOR PROFILE GRINDING WHEELS Harold S. Hallewell, Connaught Works, Uxbridge Road, wlgdon Heath, England The present invention relates to forming apparatus for profile grinding wheels, that is to apparatus for the formation on a grinding wheel of a profile which is the complement of a profile required to be ground thereby on a tool, die, gauge or other workpiece, and the invention relates more particularly to forming apparatus of the kind comprising a pantograph mechanism having a tracer member adapted to trace the profile of a template and a follower member arranged to reproduce on a smaller scale a profile traced out by the tracer member, the follower member having a forming tool adapted to engage the periphery of a grinding wheel.

In forming the profile of the grinding wheel of a horizontal spindle surface grinding machine, that is a machine in which the grinding wheel is mounted upon a horizontal spindle projecting out over a work table, the forming apparatus may be mounted upon the table with the forming tool (for example a diamond) arranged beneath the grinding wheel and displaceable in a vertical plane containing the rotational axis of the grinding wheel. It is however usually necessary to dress the grinding wheel, that is to true up the profile of the grinding Wheel, several times during a single grinding operation, and for this reason the forming apparatus is conveniently mounted at one end of the table and the workpiece at the other end of the table, the table being traversed in order to bring either the forming apparatus or the workpiece into engagement with the grinding Wheel as required. This mounting arrangement has the disadvantage that only a portion of the table is available for grinding operations and the forming apparatus, which is an instrument constructed with a very high degree of precision, is exposed to the risk of accidental damage during grinding operations. The forming apparatus may of course be removed from the table during grinding operations but this involves time wastage in resetting the apparatus for each dressing operation.

The object of the invention is to provide an improved forming apparatus and mounting therefor which overcomes the above-mentioned disadvantages.

According to the invention, there is provided forming apparatus for use with a horizontal spindle surface grinding machine and comprising a base, a carriage movable on the base, screw-threaded means for adjusting the position of the carriage on the base, and pantograph mechanism mounted upon a fixed pivot on the carriage, the pantograph mechanism having a tracer member for co operation With a template adapted to be supported on the carriage and a follower member serving for the support of a tool for forming a profile on the grinding wheel of the machine, wherein the tracer and follower members are arranged on opposite sides of the fixed pivot, and the a tes Patent 2,985,163 Patented May 23, 1961 ice disposed between the tracer and follower members the mechanism operates in reverse, that is the follower member executes movements in the reverse direction, and on a smaller scale, to movements traced out by the tracer member. Since therefore maximum outward movement of the tracer member in one direction away from the fixed pivot effects maximum outward movement of the follower member in the opposite direction away from the fixed pivot, the template must be positioned between the racer member and the fixed pivot and the overall length of the apparatus need not exceed the distance between the tracer and follower members when the pantograph mechanism is in its fully extended position.

The base can be mounted on a bracket on the main column of the grinding machine, but is preferably mounted on the bearing box for the grinding wheel spindle. In this preferred arrangement, a hollow water jacket is preferably interposed between the base and the bearing box in order to prevent transfer of heat generated by the bearings in the bearing box to the forming apparatus. The base of the apparatus is preferably mounted in slideways on the water jacket and the weight of the component parts of the apparatus so adjusted that the total weight of the apparatus is distributed fairly evenly across the bearing box, whereby the apparatus can be supported on the bearing box alone without the aid of supporting brackets. The conventional construction of bearing box for a horizontal spindle surface grinding machine includes a top cover plate to permit access to the interior of the bearing box, and the apparatus can conveniently be mounted on such a bearing box by merely removing the top cover plate and then bolting the water jacket on to v the bearing box through the lugs normally used for the bolts for the top cover plate, the bottom of the water jacket then forming a top cover for the bearing box.

In many conventional constructions of horizontal spindle surface grinding machines the wheel head, that is the bearing box together with the spindle and grinding wheel, is adjustable vertically on the main column and the forming apparatus according to the invention has the advantage that it can remain permanently in position on the wheel head, the forming tool on the follower member being offset from the grinding wheel during the grinding operations by suitable positioning of the tracer member. Morever the forming apparatus is a relatively compact assembly positioned well above the work table of the machine and is therefore not exposed to serious risk of accidental damage.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which- Figure 1 is a perspective view of the forming apparatus mounted upon the wheel head of a horizontal spindle surface grinding -machine,

Figure 2 is a part sectional elevation view on a larger scale of the forming apparatus shown in Figure I,

Figure 3 is a plan view of the forming apparatus,

Figure 4 is a detail view showing the mounting of the carriage on the base of the apparatus.

Referring to the drawings, the grinding machine comprises a frame 10 and a work table 11 movable transversely across the frame. The frame includes a vertical column positioned to the rear of the work table and a wheel head 12 is movable vertically in slideways on the column. The wheel head comprises a bearing box 13 for p a power driven spindle 14 extending horizontally out- Since the fixed pivot of the pantograph mechanism is wards across the work table and a grinding wheel 15 mounted on the free end of the spindle. The construction of the wheel head and the power means for driving the spindle are not shown in detail since they may be of any suitable conventional construction. Forming apparatus 16 for dressing the grinding wheel is mounted on the bearing box 13 of the grinding machine.

vided with a'screw (not shown) arranged to engage the slideway 18' and clamp the base firmly to the jacket after adjustment of the base on the jacket, and conduits 20 in a side wall of the jacket feed water into and away from the interior of the jacket to dissipate heat conducted to the jacket from the bearing box.

A carriage 21 is mounted on the base 17 for movement in directions transversely of the axis of the grinding wheel spindle. As shown in Figure 4 the carriage is provided with two longitudinal rails 22 depending downwards and straddling two longitudinal rails 23 on the base 17, and two rectilinear ball bearings 24 are clamped one between each adjacent pair of the rails 22, 23. The two inner races of the bearings 24 rest upon the base 17 and the two outer races of the bearings are spaced above the base and support the carriage 21. A fibre plunger 25 is slidably mounted in a recess 26 in a flange 27 at the front of the base 17, and a screw 28 in the flange 27 forces the plunger 25 against the front rail 22 to provide a light clamping elfect against vibratory movement of the carriage.

Traverse of the carriage is effected by a worm 30 and worm wheel 3-1 on the base 17 co-operating with a screwed shaft 32 extending longitudinally along the underside of the carriage. The worm wheel 31 is rotatably mounted in a saddle 33 secured in a slot in the base 17 by screws 34, and the shaft 32 is rigidly mounted at one end on a lug 29 on the carriage and extends through a screw threaded aperture in the centre of the Worm wheel 31, the worm wheel thus acting asa nut on the shaft 32. The worm 30 is drivably connected to a handle 35 at the front of the base 17, and a circular scale on the handle co-operating with an index on the base permits adjustment of the carriage to a predetermined position on the base.

The left hand end of the carriage 21 (Figures 2 and 3) is provided with a platform 36 for the support of the tracer member of the pantograph mechanism, and a template holder 37 is slidably mounted in a recess in the right hand end of the platform for movement in directions parallel to the axis of the grinding wheel spindle. Traverse of the holder 37 is effected by a fine threaded screw 38 rotatably mounted in the front end of the holder and engaging in a screw threaded aperture in the carriage. The template holder 37 projects. abovethe level of the platform and a template 39 is secured by screws 40 to the holder 37. The outer end 41 of the template 39 (that is the left hand end of the template in Figures 2 and 3) extends outwards over the platform and is formed with the profile to be traced by the tracer member of the pantograph mechanism, and the innerend of the template has a straight edge which bears against an abutment surface 42 on the top of the holder 37, the abutment surface 42 being arranged parallel to the vertical plane through the axis of the grinding wheel spindle.

The pantograph mechanism 16 comprises a front link 50 and a rear link 51 arranged parallel to one another in a horizontal plane and two side links 52, 53 also arranged parallel to one another and pivotally connected to the front and rear links to form a parallelogram linkage system, each of the links being movable generally parallel to a plane spaced from and parallel to the spindle tends from the fixed pivot 54 diagonally outwards in front of the carriage, with the front link 50 positioned above and extending across the grinding wheel. The side link 52 remote from the fixed pivot 54 extends behind the rear link 51 and a tracer member 55 is mounted in a bearing housing 56 on the free end of the link 51 for rocking movement about a vertical axis- The tracer member comprises a handle 57 above the housing 56 and a stylus 58 projecting downwards below the housing 56 and aligned with the rocking axis of the tracer member. The stylus engages the top surface of the platform 36 and is arranged to bear against the profile on the outer end 41 of the template 39. The front link 50 extends beyond the side link 53 and a follower member 59 18 mounted in a bearing housing 60 on the free end of the link 50 for rocking movement about a vertical axis. The follower member 59 extends downwards below the base 17 of the forming apparatus and is provided with a diamond cutting tool 61 positioned in the horizontal plane through the axis of the grinding wheel spindle. The lower end portion of the follower member 59 is curved outwards away from the rocking axis of the follower member and the tool 61 is arranged with its working point aligned with the rocking axis.

The tracer member 55 and the follower member 59 are coupled together by a rod 62 one end of which is pivotally connected to the tracer member 55 and the other end of which is pivotally connected to one arm of a bell crank 63 angularly movable on the pivot between the links 50, 52, and by a further rod 64 one end of which is pivotally connected to the follower member 53 and the other end of which is pivotally connected to the other arm of the bell crank 63. The rods 62, 64 thus constrain the tracer and follower members to rock in unison upon angular movement of the handle 57 on the tracer member.

Since the tracer and follower members. 55, 59 are arranged on opposite sides of the fixed pivot 54 the pantograph mechanism operates in reverse, that is forward movement of the tracer member imparts rearward movement to the follower member and movement of the tracer member towards the left imparts movement towards the right to the follower member. The profile formed on the outer end 41 of the template 39 must therefore be the reverse of the profile to be formed on the grinding wheel, but enlarged to a scale equal to the magnification factor of the pantograph mechanism.

To form a profile on the grinding wheel, the carriage 21 is first displaced by the worm and Wheel drive to a position in which the tool 61 on the follower member is offset radially outwards from the periphery of the wheel when the stylus 58 on the tracer member is engaged against the portion of the template profile nearest to the abutment surface 42 on the template holder 37. The template is then adjusted forwards and rearwards by means of the template holder adjustment screw 38 to a position in which movement of the stylus along the length of the profile of the template imparts to the tool a corresponding movement across the width of the periphery of the grinding wheel. During forming operations the stylus is passed to and fro along the profile of the template, the tool being adjusted angularly about its rocking axis by thehandle 57 of the tracer member to maintain the tool normal to the portion of the pe ripheral surface of the wheel engaged by the tool, and the tool is fed a small amount radially inwards towards the grinding wheel axis after each pass of the stylus 'along the template until the desired profile has been formed on the grinding wheel.

I claim: 7

1. In a horizontal spindle surface grinding machine, forming apparatus comprising a base mounted above the spindle of the machine, a carriage movable thereon transversely of the spindle, means for adjusting the position of the carriage on the base, and a pantograph mechanism mounted on said carriage, a fixed pivot for said pantograph mechanism on said carriage, said pantograph mechanism having a tracer member and a follower member arranged on opposite sides of said fixed pivot respectively whereby the mechanism operates in reverse, said tracer member being adapted to cooperate with a template supported on the carriage and the said follower member depending downwards below the base and adapted to support a tool for forming a profile on the grinding wheel of the machine, the forming apparatus being arranged with the tracer and follower members on opposite sides of the spindle of the grinding machine.

2. In a horizontal spindle surface grinding machine having a bearing box supporting the wheel spindle thereof, forming apparatus comprising a hollow water jacket mounted on said bearing box, said jacket having conduit means for supply and discharge of cooling fluid, a base mounted on said jacket, a carriage movable on the base transversely of the spindle, means for adjusting the position of the carriage on the base, a template holder movable on the carriage parallel to the spindle, means for adjusting the position of the template holder on the carriage, a fixed pivot for said pantograph mechanism and a pantograph mechanism mounted on said fixed pivot and having a tracer member and a follower member arranged on opposite sides of the fixed pivot whereby the mechanism operates in reverse, the said tracer member being adapted to cooperate with a template supported on said template holder and the said follower member depending downwards below the base and adapted to support a tool for forming a profile on the grinding wheel of the machine, the apparatus being arranged with the tracer and follower members on opposite sides of the spindle of the grinding machine.

3. In a horizontal spindle surface grinding machine having a bearing box supporting the wheel spindle thereof, forming apparatus comprising a hollow water jacket mounted on said bearing box and forming the top cover thereof, said jacket having conduit means for supply and discharge of cooling fluid, a base mounted on said jacket, said base having guide means extending transversely of the spindle, a carriage mounted in said guide means, means for adjusting the position of the carriage along said guide means, and a pantograph mechanism, a fixed pivot therefor mounted on said carriage and having a tracer member and a follower member arranged on opposite sides of said fixed pivot, whereby the mechanism operates in reverse, the said tracer member being adapted to cooperate with a template supported on the carriage, and the said follower member depending downwards below the base and adapted to support a tool for forming a profile on the grinding wheel of the machine, the forming apparatus being arranged with the tracer and follower members on opposite sides of the spindle of the grinding machine.

4. Forming apparatus for a horizontal spindle surface grinding machine comprising, a base having guide means extending longitudinally of the base, a carriage mounted in said guide means, means for adjusting the position of the carriage along said guide means, a pantograph mechanism, a fixed pivot therefor mounted on the carriage and having a tracer member and a follower member arranged on opposite sides of said fixed pivot whereby the mechanism operates in reverse, the said tracer member being arranged to cooperate with a template adapted to be supported on the carriage and the said follower member depending downwards below the base and adapted to support a tool for forming a profile on the grinding wheel, and means for mounting the base above the wheel spindle of the grinding machine with the guide means arranged transversely of the spindle and the tracer and follower members arranged on opposite sides thereof.

5. Forming apparatus for a horizontal spindle surface grinding machine comprising, a base having first guide means extending longitudinally of the base, a carriage mounted in said first guide means, means for adjusting the position of the carriage along said first guide means, said carriage having second guide means extending in a direction normal to said first guide means, a template holder mounted in said second guide means, means for adjusting the position of the template holder along said second guide means, a pantograph mechanism, a fixed pivot therefor mounted on the carriage and having a tracer member and a follower member arranged on opposite sides of the fixed pivot whereby the mechanism operates in reverse, the said tracer member being adapted to cooperate with a template supported on said template holder and the said follower member depending downwards below the base and adapted to support a tool for forming a profile on the grinding wheel, and means for mounting the base above the wheel spindle of the machine with the said first guide means arranged transversely of the spindle and the tracer and follower members arranged on opposite sides of the spindle.

6. Forming apparatus for a horizontal spindle surface grinding machine having a bearing box supporting the wheel spindle thereof, said apparatus comprising a water jacket having conduit means for supply and discharge of cooling fluid, a base mounted on slideways extending longitudinally along the water jacket, clamping means for rigidly securing the base to the water jacket, first guide means on said base, said first guide means extending parallel to said slideways, a carriage mounted in said first guide means, means for adjusting the position of said carriage along said first guide means, second guide means on said carriage, said second guide means extending in a direction normal to said first guide means, a template holder mounted in said second guide means, means for adjusting the position of the template holder along said second guide means, a pantograph mechanism, a fixed pivot therefor mounted on said carriage and having a tracer member and a follower member arranged on opposite sides of said fixed pivot whereby the mechanism operates in reverse, said tracer member being adapted to cooperate with a template supported on said template holder and said follower member depending downwards below the base and adapted to support a tool for forming a profile on the wheel of said grinding machine, and means for mounting the water jacket on the bearing box of the grinding machine with the first guide means arranged transversely of the spindle and the tracer and fol lower members arranged on opposite sides of the spindle.

7. In a surface grinding machine having a wheel head rotatably supporting a spindle carrying a grinding wheel, wheel forming apparatus comprising a base mounted on said wheel head near the spindle of the machine, a carriage movable on said base transversely of the spindle, means for adjusting the position of the carriage on the base, and a pantograph mechanism mounted on said carriage, a fixed pivot for said pantograph mechanism on said carriage, said pantograph mechanism having a pinrality of links generally defining a parallelogram, each of said links being movable generally in a plane spaced from and parallel to said spindle, said pantograph mechanism having a tracer member and a follower member arranged on opposite sides of said fixed pivot, respectively, whereby the pantograph mechanism operates in reverse, said tracer member being adapted to cooperate with a template supported on the carriage, and said follower member being offset with respect to said parallelogram to support a tool for forming a profile on the grinding wheel of the machine with said tool being movable essentially both radially and axially with respect to the axis of said spindle, the forming apparatus being arranged with said tracer and follower members on opposite sides of the spindle as seen in a direction normal to said parallelogram.

8. In a surface grinding machine having wheel head rotatably supporting a spindle carrying a grinding wheel, wheel forming apparatus comprising a base mounted on said Wheel head near the spindle of the machine, a pantograph mechanism, a pivot including means for mounting said pantograph mechanism on said base, said pantograph mechanism comprising four links defining a parallelogram, two of said links being pivotally supported at said pivot means for movement in parallel planes paralleling the axis of said spindle, said pivot means having a pivotal axis defining one corner of the parallelogram, said pantograph mechanism having its two other links pivotally connected to each other at the diagonally opposite corner of said parallelogram and pivotally connected, respectively, to the first two links at the two remaining corners of the parallelogram, a tracer member secured to one of said other links and a wheel forming tool secured to the other of said other links, said tracer member, and said wheel dressing tool lying at all times in a plane containing the axis of said pivot means, with said tool and said tracer being located on opposite sides of said axis, means for supporting said tool with a forming tip of the latter being ofiset from said parallel planes and being movable in another plane generally parallel thereto to provide movement of said forming tip generally radially of said grinding wheel, template means supported on said base and engageable by said tracer member, said base including pivot means being so located relative to the spindle of the machine that said tracer member and said forming tool are located on opposite sides of the spindle axis when seen in a direction normal to said first-mentioned planes, and means for adjusting the position of said pivot means relative to said grinding Wheel to position said forming tool relative to said wheel for forming a profile on the latter by movement of said tracer member along said template means.

9. In a surface grinding machine having a spindle carrying a grinding wheel, wheel forming apparatus comprising a base mounted near the spindle of the machine, a pantograph mechanism with a carriage therefor adjustably mounted on said base, pivot means for mounting said pantograph mechanism on said carriage, said pantograph mechanism comprising four links defining a parallelogram, two of said links being pivotally supported at said pivot means for movement in parallel planes paralleling the axis of said spindle, said pivot means having a pivotal axis defining one corner of the parallelogram, said pantograph mechanism having its two other links pivotally connected to each other at the diagonally opposite corner of said parallelogram and pivotally connected, respectively to the first two links at the two remaining corners of the parallelogram, a tracer member secured to one of said other links and a wheel forming tool secured to the other of said other links, said tracer member and said wheel dressing tool lying at all times in a plane containing the axis of said pivot means, with said tool and said tracer being located on opposite sides of said axis, means for supporting said tool with a forming tip of the latter being offset from said first-mentioned planes and being movable in another plane generally parallel thereto to provide movement of said forming tip generally radially of said grinding wheel, template means supported on said carriage and engageable by said tracer member, said pivot means being so located with respect to the spindle of the machine that said tracer member and said forming tool are located on opposite sides of the spindle axis when seen in a direction normal to said first-mentioned planes, and means for adjusting the position relative to said grinding wheel to position said forming tool relative to said wheel for forming a profile on the latter by movement of said tracer member along said template means.

References Cited in the file of this patent UNITED STATES PATENTS 469,047 Otto Feb. 16, 1892 1,594,607 Engelmann Aug. 3, 1926 2,380,747 Goetze July 31, 1945 2,452,509 Victory Oct. 26, 1948 2,469,844 Porter et al May 10, 1949 2,532,581 Triggs Dec. 5, 1950 2,538,532 Oliver Jan. 16, 1951 2,575,228 Moore Nov. 13, 1951 

